The joining of surfaces plays a part in many uses. Thus, for example, layers are laminated in composite systems or protective films are applied to surfaces which are to be protected. For many uses such as in wafer processing for the semiconductor industry, it is crucial to achieve precision in bonding, for example when aligning the surfaces which are to be joined relative to one another or when setting the adhesive strength which exists after bonding.
Thus, with the objective of protecting wafers for subsequent processing steps, such as rear side metallization or thinning, protective layers and/or supporting layers are provided in the region of the side with the electronic components. The function of these layers is to stabilize the wafer to be processed and to protect it against mechanical stresses on the side to be protected. For this purpose, substrates which are configured as circular discs, such as a further wafer or a glass pane which stabilizes the wafer to be processed (also in the subsequently processed state, for example a thinned state) are often joined with the wafer to be processed by means of an interlayer. The interlayer can consist, for example of an adhesive or of polymeric material. Bonding is often carried out under mechanical pressure, for example, to ensure a positive interlocking and/or under the effect of heat to allow a join, for example, by means of a chemical change in the interlayer.
A method and device for bonding wafers are known, for example from AT 504 567 A2. In this case, the surfaces to be joined (bonded) are pressed against one another by means of pressure plates, with heat acting simultaneously or subsequently on the material to be bonded.
In this case, the expense and complexity of the apparatus is a problem and it is likewise difficult to ensure that in reality the pressure acts in a completely uniform manner over the entire surface. In addition, relatively high pressures are exerted on the items to be bonded, so that there is a high mechanical stress and furthermore, a thermal loading is necessary
Comparable problems arise in the bonding methods known hitherto in the art.